ISSUE FOCUS FEED & ADDITIVE MAGAZINE July 2023 45 cluding housing modifications, genetic selection for heat-tolerant cows and nutritional management. The first step dairy farmers can take is providing shade to effectively block solar radiation, as exposure is a key concern for ruminant health and welfare. Additional evaporative cooling and air ventilation can also be implemented; however, in contrast with confinement dairies, optimal cooling strategies for grazing cattle have not yet been identified (Dahl et al., 2020). From a husbandry standpoint, the breed, age and lactation phase are known to influence the risk of occurrence of heat stress in cows (Bernabucci et al., 2014). Proper breed selection is thus a valuable tool for sustaining animal production in an increasingly challenging environment (Silanikove, 1992). Genetically altering the thermal tolerance of high-production animals has, however, proven to be difficult (Collier et al., 2019). Additionally, strategic nutrition management is increasingly of interest to help improve the animal’s response to high heat. For example, it has been found that feeding dietary fat (rumen inert/rumen bypass) reduces rectal temperature and increases milk yield in dairy cows (Wang et al. 2010). Studies also indicate the importance of antioxidant supplementation in both in vivo and in vitro trials, such as the thermo-protective role of vitamin E in buffalo cows (Megahed et al., 2008). Furthermore, certain feed additives can be used to alleviate heat stress. Much attention has been placed on the use of live microorganisms and yeast products to help modulate the immune system, helping the animal fortify its defenses against stressors. Another area of research has been with plant extracts such as capsaicin. Capsaicin may help mitigate heat stress through vasodilation, improvements in feed eating patterns and water intake. ADM’s FreshUp approach is a heat stress solution for ruminants, leveraging the synergistic effects of specialty nutrition formulations to counter the negative impact of high temperatures on animal outputs. This unique blend of natural ingredients, including plant extracts and Pichia guilliermondii inactivated yeast, can improve animal thermoregulation and has been tested at university and field locations across North America for more than 15 years. Experimental trials show greater feed efficiency in dairy cows and higher milk yields in cows (ADM internal research, 2006-2020). CONSEQUENCES OF CLIMATE CHANGE Ruminants’ prolonged exposure to high heat conditions results in significant changes in the physiological and biochemical parameters in the animal, making heat stress one of the most concerning issues facing producers. This is particularly relevant in the case of high-producing dairy cows. Mitigating heat stress is crucial to achieving efficient, profitable and sustainable animal agriculture operations. However, this may become increasingly costly and difficult to implement. According to the World Meteorological Organization (WMO), global temperatures are expected to set new records in the next five years. The annual mean global near-surface temperature for each year between 2023 and 2027 is predicted to be between 1.1°C and 1.8°C higher than pre-industrial levels (i.e., the 1850-1900 average). Climate change will be an ongoing challenge, given the projected magnitude of potential heat stress conditions as global temperatures continue to climb.
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